Blog Archive

Tuesday, 11 March 2008

Weekly BioNews 3 - 10 Mar 2008

- History Of Life Seen In The Structure Of Transfer RNA

ScienceDaily (Mar. 10, 2008)

Transfer RNA is an ancient molecule, central to every task a cell performs and thus essential to all life. A new study from the University of Illinois indicates that it is also a great historian, preserving some of the earliest and most profound events of the evolutionary past in its structure.

The study, co-written by Gustavo Caetano-Anolles,* a professor of crop sciences, and postdoctoral researcher Feng-Jie Sun, appears March 7 in PLoS Computational Biology.

All tRNAs assemble themselves into a shape that, if flattened, resembles a cloverleaf. Patterns in these structures give clues to early evolutionary history. The red areas of the molecule pictured above are the most ancient.

Of the thousands of RNAs so far identified, transfer RNA (tRNA) is the most direct intermediary between genes and proteins. Like many other RNAs (ribonucleic acids), tRNA aids in translating genes into the chains of amino acids that make up proteins. With the help of a highly targeted enzyme, each tRNA molecule recognizes and latches onto a specific amino acid, which it carries into the protein-building machinery. In order to successfully add its amino acid to the end of a growing protein, tRNA must also accurately read a coded segment of messenger RNA, which gives instructions for the exact sequence of amino acids in the protein.

UC Irvine researchers have discovered a dramatically improved method for genetically manipulating human embryonic stem cells, making it easier for scientists to study and potentially treat thousands of disorders ranging from Huntington’s disease to muscular dystrophy and diabetes.

The technique for the first time blends two existing cell-handling methods to improve cell survival rates and increase the efficiency of inserting DNA into cells. The new approach is up to 100 times more efficient than current methods at producing human embryonic stem cells with desired genetic alterations.

“The ability to generate large quantities of cells with altered genes opens the door to new research into many devastating disorders,” said Peter Donovan, professor of biological chemistry and developmental and cell biology at UCI, and co-director of the UCI Sue and Bill Gross Stem Cell Research Center. “Not only will it allow us to study diseases more in-depth, it also could be a key step in the successful development of future stem cell therapies.”

One strategy being pursued to develop new vaccines against infectious diseases is DNA vaccination. The idea is that following administration of a DNA vaccine, the body converts the information in the DNA vaccine into a protein that activates an immune response. However, current DNA vaccines induce relatively weak immune responses even if administered multiple times. New data, generated in mice, by Ralph Steinman and colleagues, at the Rockefeller University, New York, has now identified a way to make DNA vaccines more potent.

Solving a long-standing biological mystery, UCLA stem cell researchers have discovered that blood stem cells, the cells that later differentiate into all the cells in the blood supply, originate and are nurtured in the placenta.

The discovery may allow researchers to mimic the specific embryonic microenvironment necessary for development of blood stem cells in cell culture and grow them for use in treating diseases like leukemia and aplastic anemia, said Dr. Hanna Mikkola, a researcher in the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research and senior author of the study.

Researchers at the Gladstone Institute of Cardiovascular Disease (GICD) and the University of California, San Francisco have identified for the first time how tiny genetic factors called microRNAs may influence the differentiation of pluripotent embryonic stem (ES) cells into cardiac muscle. As reported in the journal Cell Stem Cell, scientists in the lab of GICD Director, Deepak Srivastava, MD, demonstrated that two microRNAs, miR-1 and miR-133, which have been associated with muscle development, not only encourage heart muscle formation, but also actively suppress genes that could turn the ES cells into undesired cells like neurons or bone.